Irritable bowel syndrome (IBS) is a chronic digestive condition that affects the large intestine (colon). IBS - unlike inflammatory bowel diseases (IBD) such as Crohn's and colitis - does NOT cause changes in bowel tissue.
The signs and symptoms of IBS can vary widely and often resemble those of other digestive diseases. The effects of IBS can range from mild inconvenience to severe debilitation. Because IBS is unpredictable, the condition can disrupt everyday life, preventing someone from going to work, attending school, or taking care of their family. Severe IBS can even limit a person’s potential, as the symptoms can impair nearly every aspect of their well-being, from their physical health to their economic state. Common IBS symptoms include:
*When changes in bowel habits are persistent, or occur with other symptoms, including rectal bleeding, abdominal pain that progresses at night or unexplained weight loss, it may indicate a more serious condition, such as colon cancer.
It's not known exactly what causes irritable bowel syndrome. The walls of the intestines are lined with muscles that contract and relax to move food through your digestive tract. If you have IBS, the GI muscles do not contract normally. Common triggers include:
- Foods. The specific foods that trigger symptoms vary greatly. Dairy and wheat are common triggers.
- Stress. Most people find symptoms are worse during periods of increased stress.
- Other illnesses. Sometimes another illness, such as gastroenteritis can lead to IBS.
The signs of IBS are similar to many other conditions, so diagnosis is often a process of ruling out other causes. If you have signs suggesting another condition, your provider will order additional tests. Some “red flag” symptoms that may indicate more serious conditions include:
- New onset after age 50
- Abdominal pain
- Persistent or recurring nausea & vomiting
- Diarrhea that is persistent or awakens you from sleep
IBS is a diagnosis of exclusion. Your doctor will exclude more serious issues through blood or stool tests that exclude anemia, infection, autoimmune disease, food allergies such as celiac disease and inflammation suggestive of IBD. Doctors may order imaging tests to get a better look at the organs of the GI tract.
Doctors sometimes order an endoscopic evaluation, which are procedures that allow doctors to see inside the digestive tract. A colonoscopy is a procedure in which a doctor uses a long, thin tube with a camera to see inside a patient’s colon. A flexible sigmoidoscopy allows a doctor to view the rectum and sigmoid colon, which is the last part of the large intestine. An upper endoscopy is similar, except it looks at the esophagus, stomach and first part of the small intestine.
Because it's not clear what causes irritable bowel syndrome, treatment focuses on the relief of symptoms. In most cases, your doctor can help you control mild symptoms by recommending lifestyle changes. If your problems are more severe, treatment may involve medications.
Frequently Asked Questions
What is IBS?
Irritable bowel syndrome (IBS) is a disorder affecting the bowel, also known as the colon or large intestine. IBS causes gas, pain in the belly, diarrhea, and constipation.
Why do they call it “irritable” bowel?
The word “irritable” refers to unusual sensitivity of the nerve endings in the wall of the intestine. These nerve endings control the muscle function of the gut and sensations in the gut. This means that even normal activity that could stimulate bowel activity, such as eating a meal or feeling stress, can cause a greater response for people with IBS.
How common is IBS?
IBS is a common issue. In fact, between 25 and 45 million people in the United States has IBS. The condition affects females more often – approximately 2 out of every 3 people with IBS is female. IBS affects people of all ages, including children. Most people with IBS are under the age of 50.
Is IBS a serious illness?
The seriousness of IBS varies from person to person. For some, IBS causes manageable symptoms that do not interfere with daily life. For others, though, IBS can be disabling.
Is IBS a Chronic Condition?
IBS can persist for years, which makes it a chronic condition. Symptoms fade over time for some people but not for others. In fact, about 10 percent of people with IBS get better; the prevalence of IBS remains the same, though, because about the same number of people develop the syndrome over the same period.
How do I know if I have IBS?
Your doctor can diagnose IBS. Diagnosis requires a careful review of your symptoms, a physical evaluation, and selected diagnostic procedures or tests.
My doctor says I have IBS, but the tests show nothing wrong. Is that normal?
IBS is a diagnosis of exclusion, which means doctors may diagnose patients with IBS after ruling out other conditions. Your doctor might also provide a diagnosis of IBS based on the specific pattern of symptoms you experience.
What is a functional bowel disorder?
IBS is a functional bowel disorder, which means there is a problem with the way the bowels work and that it is not a problem with their structure.
Is IBS a risk factor for other serious diseases?
Fortunately, IBS does not appear to be associated with other serious diseases.
Can the menstrual cycle affect IBS symptoms?
The menstrual cycle features changes in hormone levels, and these changes can influence the function of the bowels. IBS symptoms tend to worsen at different times of the cycle, particularly during menstrual periods.
What causes bloating and gas?
Bloating and gas are common in people with IBS. Bloating may develop after eating gas-forming foods, or be the result of gas moving slowly through the bowel. Increased sensitivity to food and gas may also cause bloating.
What is the treatment for IBS?
Treatment for IBS usually involves dietary changes, such as increasing fiber and limiting cheese and milk, regular exercise, relaxation techniques, and medications.
Medications may include fiber supplements, laxatives, anti-diarrheal drugs, drugs to control spasms, pain medications, and antidepressants. Other medications may relax the colon and slow the movement of waste material through it, drugs to control bacterial overgrowths, and prescriptions to increase fluid secretion into the colon to make stool easier to pass.